/* SDSLib 2.0 -- A C dynamic strings library
 *
 * Copyright (c) 2006-2015, Salvatore Sanfilippo <antirez at gmail dot com>
 * Copyright (c) 2015, Oran Agra
 * Copyright (c) 2015, Redis Labs, Inc
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   * Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *   * Neither the name of Redis nor the names of its contributors may be used
 *     to endorse or promote products derived from this software without
 *     specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <assert.h>
#include "../lib/sds.h"
#include "../lib/sdsalloc.h"

static inline int sdsHdrSize ( char type )
{
    switch ( type & SDS_TYPE_MASK )
    {
        case SDS_TYPE_5:
            return sizeof (struct sdshdr5 );
        case SDS_TYPE_8:
            return sizeof (struct sdshdr8 );
        case SDS_TYPE_16:
            return sizeof (struct sdshdr16 );
        case SDS_TYPE_32:
            return sizeof (struct sdshdr32 );
        case SDS_TYPE_64:
            return sizeof (struct sdshdr64 );
    }
    return 0;
}

static inline char sdsReqType ( size_t string_size )
{
    if ( string_size < 32 )
        return SDS_TYPE_5;
    if ( string_size < 0xff )
        return SDS_TYPE_8;
    if ( string_size < 0xffff )
        return SDS_TYPE_16;
    if ( string_size < 0xffffffff )
        return SDS_TYPE_32;
    return SDS_TYPE_64;
}

/* Create a new sds string with the content specified by the 'init' pointer
 * and 'initlen'.
 * If NULL is used for 'init' the string is initialized with zero bytes.
 *
 * The string is always null-termined (all the sds strings are, always) so
 * even if you create an sds string with:
 *
 * mystring = sdsnewlen("abc",3);
 *
 * You can print the string with printf() as there is an implicit \0 at the
 * end of the string. However the string is binary safe and can contain
 * \0 characters in the middle, as the length is stored in the sds header. */
sds sdsnewlen ( const void *init, size_t initlen )
{
    void *sh;
    sds s;
    char type = sdsReqType (initlen);
    /* Empty strings are usually created in order to append. Use type 8
     * since type 5 is not good at this. */
    if ( type == SDS_TYPE_5 && initlen == 0 ) type = SDS_TYPE_8;
    int hdrlen = sdsHdrSize (type);
    unsigned char *fp; /* flags pointer. */

    sh = s_malloc (hdrlen + initlen + 1);
    if ( ! init )
        memset (sh, 0, hdrlen + initlen + 1);
    if ( sh == NULL ) return NULL;
    s = ( char* ) sh + hdrlen;
    fp = ( ( unsigned char* ) s ) - 1;
    switch ( type )
    {
        case SDS_TYPE_5:
        {
            *fp = type | ( initlen << SDS_TYPE_BITS );
            break;
        }
        case SDS_TYPE_8:
        {
            SDS_HDR_VAR (8, s);
            sh->len = initlen;
            sh->alloc = initlen;
            *fp = type;
            break;
        }
        case SDS_TYPE_16:
        {
            SDS_HDR_VAR (16, s);
            sh->len = initlen;
            sh->alloc = initlen;
            *fp = type;
            break;
        }
        case SDS_TYPE_32:
        {
            SDS_HDR_VAR (32, s);
            sh->len = initlen;
            sh->alloc = initlen;
            *fp = type;
            break;
        }
        case SDS_TYPE_64:
        {
            SDS_HDR_VAR (64, s);
            sh->len = initlen;
            sh->alloc = initlen;
            *fp = type;
            break;
        }
    }
    if ( initlen && init )
        memcpy (s, init, initlen);
    s[initlen] = '\0';
    return s;
}

/* Create an empty (zero length) sds string. Even in this case the string
 * always has an implicit null term. */
sds sdsempty ( void )
{
    return sdsnewlen ("", 0);
}

/* Create a new sds string starting from a null terminated C string. */
sds sdsnew ( const char *init )
{
    size_t initlen = ( init == NULL ) ? 0 : strlen (init);
    return sdsnewlen (init, initlen);
}

/* Duplicate an sds string. */
sds sdsdup ( const sds s )
{
    return sdsnewlen (s, sdslen (s));
}

/* Free an sds string. No operation is performed if 's' is NULL. */
void sdsfree ( sds s )
{
    if ( s == NULL ) return;
    s_free (( char* ) s - sdsHdrSize (s[- 1]));
}

/* Set the sds string length to the length as obtained with strlen(), so
 * considering as content only up to the first null term character.
 *
 * This function is useful when the sds string is hacked manually in some
 * way, like in the following example:
 *
 * s = sdsnew("foobar");
 * s[2] = '\0';
 * sdsupdatelen(s);
 * printf("%d\n", sdslen(s));
 *
 * The output will be "2", but if we comment out the call to sdsupdatelen()
 * the output will be "6" as the string was modified but the logical length
 * remains 6 bytes. */
void sdsupdatelen ( sds s )
{
    int reallen = strlen (s);
    sdssetlen (s, reallen);
}

/* Modify an sds string in-place to make it empty (zero length).
 * However all the existing buffer is not discarded but set as free space
 * so that next append operations will not require allocations up to the
 * number of bytes previously available. */
void sdsclear ( sds s )
{
    sdssetlen (s, 0);
    s[0] = '\0';
}

/* Enlarge the free space at the end of the sds string so that the caller
 * is sure that after calling this function can overwrite up to addlen
 * bytes after the end of the string, plus one more byte for nul term.
 *
 * Note: this does not change the *length* of the sds string as returned
 * by sdslen(), but only the free buffer space we have. */
sds sdsMakeRoomFor ( sds s, size_t addlen )
{
    void *sh, *newsh;
    size_t avail = sdsavail (s);
    size_t len, newlen;
    char type, oldtype = s[- 1] & SDS_TYPE_MASK;
    int hdrlen;

    /* Return ASAP if there is enough space left. */
    if ( avail >= addlen ) return s;

    len = sdslen (s);
    sh = ( char* ) s - sdsHdrSize (oldtype);
    newlen = ( len + addlen );
    if ( newlen < SDS_MAX_PREALLOC )
        newlen *= 2;
    else
        newlen += SDS_MAX_PREALLOC;

    type = sdsReqType (newlen);

    /* Don't use type 5: the user is appending to the string and type 5 is
     * not able to remember empty space, so sdsMakeRoomFor() must be called
     * at every appending operation. */
    if ( type == SDS_TYPE_5 ) type = SDS_TYPE_8;

    hdrlen = sdsHdrSize (type);
    if ( oldtype == type )
    {
        newsh = s_realloc (sh, hdrlen + newlen + 1);
        if ( newsh == NULL ) return NULL;
        s = ( char* ) newsh + hdrlen;
    }
    else
    {
        /* Since the header size changes, need to move the string forward,
         * and can't use realloc */
        newsh = s_malloc (hdrlen + newlen + 1);
        if ( newsh == NULL ) return NULL;
        memcpy (( char* ) newsh + hdrlen, s, len + 1);
        s_free (sh);
        s = ( char* ) newsh + hdrlen;
        s[- 1] = type;
        sdssetlen (s, len);
    }
    sdssetalloc (s, newlen);
    return s;
}

/* Reallocate the sds string so that it has no free space at the end. The
 * contained string remains not altered, but next concatenation operations
 * will require a reallocation.
 *
 * After the call, the passed sds string is no longer valid and all the
 * references must be substituted with the new pointer returned by the call. */
sds sdsRemoveFreeSpace ( sds s )
{
    void *sh, *newsh;
    char type, oldtype = s[- 1] & SDS_TYPE_MASK;
    int hdrlen;
    size_t len = sdslen (s);
    sh = ( char* ) s - sdsHdrSize (oldtype);

    type = sdsReqType (len);
    hdrlen = sdsHdrSize (type);
    if ( oldtype == type )
    {
        newsh = s_realloc (sh, hdrlen + len + 1);
        if ( newsh == NULL ) return NULL;
        s = ( char* ) newsh + hdrlen;
    }
    else
    {
        newsh = s_malloc (hdrlen + len + 1);
        if ( newsh == NULL ) return NULL;
        memcpy (( char* ) newsh + hdrlen, s, len + 1);
        s_free (sh);
        s = ( char* ) newsh + hdrlen;
        s[- 1] = type;
        sdssetlen (s, len);
    }
    sdssetalloc (s, len);
    return s;
}

/* Return the total size of the allocation of the specifed sds string,
 * including:
 * 1) The sds header before the pointer.
 * 2) The string.
 * 3) The free buffer at the end if any.
 * 4) The implicit null term.
 */
size_t sdsAllocSize ( sds s )
{
    size_t alloc = sdsalloc (s);
    return sdsHdrSize (s[- 1]) + alloc + 1;
}

/* Return the pointer of the actual SDS allocation (normally SDS strings
 * are referenced by the start of the string buffer). */
void *sdsAllocPtr ( sds s )
{
    return ( void* ) ( s - sdsHdrSize (s[- 1]) );
}

/* Increment the sds length and decrements the left free space at the
 * end of the string according to 'incr'. Also set the null term
 * in the new end of the string.
 *
 * This function is used in order to fix the string length after the
 * user calls sdsMakeRoomFor(), writes something after the end of
 * the current string, and finally needs to set the new length.
 *
 * Note: it is possible to use a negative increment in order to
 * right-trim the string.
 *
 * Usage example:
 *
 * Using sdsIncrLen() and sdsMakeRoomFor() it is possible to mount the
 * following schema, to cat bytes coming from the kernel to the end of an
 * sds string without copying into an intermediate buffer:
 *
 * oldlen = sdslen(s);
 * s = sdsMakeRoomFor(s, BUFFER_SIZE);
 * nread = read(fd, s+oldlen, BUFFER_SIZE);
 * ... check for nread <= 0 and handle it ...
 * sdsIncrLen(s, nread);
 */
void sdsIncrLen ( sds s, int incr )
{
    unsigned char flags = s[- 1];
    size_t len;
    switch ( flags & SDS_TYPE_MASK )
    {
        case SDS_TYPE_5:
        {
            unsigned char *fp = ( ( unsigned char* ) s ) - 1;
            unsigned char oldlen = SDS_TYPE_5_LEN (flags);
            assert (( incr > 0 && oldlen + incr < 32 ) || ( incr < 0 && oldlen >= ( unsigned int ) ( - incr ) ));
            *fp = SDS_TYPE_5 | ( ( oldlen + incr ) << SDS_TYPE_BITS );
            len = oldlen + incr;
            break;
        }
        case SDS_TYPE_8:
        {
            SDS_HDR_VAR (8, s);
            assert (( incr >= 0 && sh->alloc - sh->len >= incr ) || ( incr < 0 && sh->len >= ( unsigned int ) ( - incr ) ));
            len = ( sh->len += incr );
            break;
        }
        case SDS_TYPE_16:
        {
            SDS_HDR_VAR (16, s);
            assert (( incr >= 0 && sh->alloc - sh->len >= incr ) || ( incr < 0 && sh->len >= ( unsigned int ) ( - incr ) ));
            len = ( sh->len += incr );
            break;
        }
        case SDS_TYPE_32:
        {
            SDS_HDR_VAR (32, s);
            assert (( incr >= 0 && sh->alloc - sh->len >= ( unsigned int ) incr ) || ( incr < 0 && sh->len >= ( unsigned int ) ( - incr ) ));
            len = ( sh->len += incr );
            break;
        }
        case SDS_TYPE_64:
        {
            SDS_HDR_VAR (64, s);
            assert (( incr >= 0 && sh->alloc - sh->len >= ( uint64_t ) incr ) || ( incr < 0 && sh->len >= ( uint64_t ) ( - incr ) ));
            len = ( sh->len += incr );
            break;
        }
        default: len = 0; /* Just to avoid compilation warnings. */
    }
    s[len] = '\0';
}

/* Grow the sds to have the specified length. Bytes that were not part of
 * the original length of the sds will be set to zero.
 *
 * if the specified length is smaller than the current length, no operation
 * is performed. */
sds sdsgrowzero ( sds s, size_t len )
{
    size_t curlen = sdslen (s);

    if ( len <= curlen ) return s;
    s = sdsMakeRoomFor (s, len - curlen);
    if ( s == NULL ) return NULL;

    /* Make sure added region doesn't contain garbage */
    memset (s + curlen, 0, ( len - curlen + 1 )); /* also set trailing \0 byte */
    sdssetlen (s, len);
    return s;
}

/* Append the specified binary-safe string pointed by 't' of 'len' bytes to the
 * end of the specified sds string 's'.
 *
 * After the call, the passed sds string is no longer valid and all the
 * references must be substituted with the new pointer returned by the call. */
sds sdscatlen ( sds s, const void *t, size_t len )
{
    size_t curlen = sdslen (s);

    s = sdsMakeRoomFor (s, len);
    if ( s == NULL ) return NULL;
    memcpy (s + curlen, t, len);
    sdssetlen (s, curlen + len);
    s[curlen + len] = '\0';
    return s;
}

/* Append the specified null termianted C string to the sds string 's'.
 *
 * After the call, the passed sds string is no longer valid and all the
 * references must be substituted with the new pointer returned by the call. */
sds sdscat ( sds s, const char *t )
{
    return sdscatlen (s, t, strlen (t));
}

/* Append the specified sds 't' to the existing sds 's'.
 *
 * After the call, the modified sds string is no longer valid and all the
 * references must be substituted with the new pointer returned by the call. */
sds sdscatsds ( sds s, const sds t )
{
    return sdscatlen (s, t, sdslen (t));
}

/* Destructively modify the sds string 's' to hold the specified binary
 * safe string pointed by 't' of length 'len' bytes. */
sds sdscpylen ( sds s, const char *t, size_t len )
{
    if ( sdsalloc (s) < len )
    {
        s = sdsMakeRoomFor (s, len - sdslen (s));
        if ( s == NULL ) return NULL;
    }
    memcpy (s, t, len);
    s[len] = '\0';
    sdssetlen (s, len);
    return s;
}

/* Like sdscpylen() but 't' must be a null-termined string so that the length
 * of the string is obtained with strlen(). */
sds sdscpy ( sds s, const char *t )
{
    return sdscpylen (s, t, strlen (t));
}

/* Helper for sdscatlonglong() doing the actual number -> string
 * conversion. 's' must point to a string with room for at least
 * SDS_LLSTR_SIZE bytes.
 *
 * The function returns the length of the null-terminated string
 * representation stored at 's'. */
#define SDS_LLSTR_SIZE 21

int sdsll2str ( char *s, long long value )
{
    char *p, aux;
    unsigned long long v;
    size_t l;

    /* Generate the string representation, this method produces
     * an reversed string. */
    v = ( value < 0 ) ? -value : value;
    p = s;
    do
    {
        *p ++ = '0' + ( v % 10 );
        v /= 10;
    }
    while ( v );
    if ( value < 0 ) *p ++ = '-';

    /* Compute length and add null term. */
    l = p - s;
    *p = '\0';

    /* Reverse the string. */
    p --;
    while ( s < p )
    {
        aux = * s;
        *s = * p;
        *p = aux;
        s ++;
        p --;
    }
    return l;
}

/* Identical sdsll2str(), but for unsigned long long type. */
int sdsull2str ( char *s, unsigned long long v )
{
    char *p, aux;
    size_t l;

    /* Generate the string representation, this method produces
     * an reversed string. */
    p = s;
    do
    {
        *p ++ = '0' + ( v % 10 );
        v /= 10;
    }
    while ( v );

    /* Compute length and add null term. */
    l = p - s;
    *p = '\0';

    /* Reverse the string. */
    p --;
    while ( s < p )
    {
        aux = * s;
        *s = * p;
        *p = aux;
        s ++;
        p --;
    }
    return l;
}

/* Create an sds string from a long long value. It is much faster than:
 *
 * sdscatprintf(sdsempty(),"%lld\n", value);
 */
sds sdsfromlonglong ( long long value )
{
    char buf[SDS_LLSTR_SIZE];
    int len = sdsll2str (buf, value);

    return sdsnewlen (buf, len);
}

/* Like sdscatprintf() but gets va_list instead of being variadic. */
sds sdscatvprintf ( sds s, const char *fmt, va_list ap )
{
    va_list cpy;
    char staticbuf[1024], *buf = staticbuf, *t;
    size_t buflen = strlen (fmt)*2;

    /* We try to start using a static buffer for speed.
     * If not possible we revert to heap allocation. */
    if ( buflen > sizeof (staticbuf ) )
    {
        buf = s_malloc (buflen);
        if ( buf == NULL ) return NULL;
    }
    else
    {
        buflen = sizeof (staticbuf );
    }

    /* Try with buffers two times bigger every time we fail to
     * fit the string in the current buffer size. */
    while ( 1 )
    {
        buf[buflen - 2] = '\0';
        va_copy (cpy, ap);
        vsnprintf (buf, buflen, fmt, cpy);
        va_end (cpy);
        if ( buf[buflen - 2] != '\0' )
        {
            if ( buf != staticbuf ) s_free (buf);
            buflen *= 2;
            buf = s_malloc (buflen);
            if ( buf == NULL ) return NULL;
            continue;
        }
        break;
    }

    /* Finally concat the obtained string to the SDS string and return it. */
    t = sdscat (s, buf);
    if ( buf != staticbuf ) s_free (buf);
    return t;
}

/* Append to the sds string 's' a string obtained using printf-alike format
 * specifier.
 *
 * After the call, the modified sds string is no longer valid and all the
 * references must be substituted with the new pointer returned by the call.
 *
 * Example:
 *
 * s = sdsnew("Sum is: ");
 * s = sdscatprintf(s,"%d+%d = %d",a,b,a+b).
 *
 * Often you need to create a string from scratch with the printf-alike
 * format. When this is the need, just use sdsempty() as the target string:
 *
 * s = sdscatprintf(sdsempty(), "... your format ...", args);
 */
sds sdscatprintf ( sds s, const char *fmt, ... )
{
    va_list ap;
    char *t;
    va_start (ap, fmt);
    t = sdscatvprintf (s, fmt, ap);
    va_end (ap);
    return t;
}

/* This function is similar to sdscatprintf, but much faster as it does
 * not rely on sprintf() family functions implemented by the libc that
 * are often very slow. Moreover directly handling the sds string as
 * new data is concatenated provides a performance improvement.
 *
 * However this function only handles an incompatible subset of printf-alike
 * format specifiers:
 *
 * %s - C String
 * %S - SDS string
 * %i - signed int
 * %I - 64 bit signed integer (long long, int64_t)
 * %u - unsigned int
 * %U - 64 bit unsigned integer (unsigned long long, uint64_t)
 * %% - Verbatim "%" character.
 */
sds sdscatfmt ( sds s, char const *fmt, ... )
{
    size_t initlen = sdslen (s);
    const char *f = fmt;
    int i;
    va_list ap;

    va_start (ap, fmt);
    f = fmt; /* Next format specifier byte to process. */
    i = initlen; /* Position of the next byte to write to dest str. */
    while ( *f )
    {
        char next, *str;
        size_t l;
        long long num;
        unsigned long long unum;

        /* Make sure there is always space for at least 1 char. */
        if ( sdsavail (s) == 0 )
        {
            s = sdsMakeRoomFor (s, 1);
        }

        switch ( *f )
        {
            case '%':
                next = * ( f + 1 );
                f ++;
                switch ( next )
                {
                    case 's':
                    case 'S':
                        str = va_arg (ap, char*);
                        l = ( next == 's' ) ? strlen (str) : sdslen (str);
                        if ( sdsavail (s) < l )
                        {
                            s = sdsMakeRoomFor (s, l);
                        }
                        memcpy (s + i, str, l);
                        sdsinclen (s, l);
                        i += l;
                        break;
                    case 'i':
                    case 'I':
                        if ( next == 'i' )
                            num = va_arg (ap, int);
                        else
                            num = va_arg (ap, long long);
                    {
                        char buf[SDS_LLSTR_SIZE];
                        l = sdsll2str (buf, num);
                        if ( sdsavail (s) < l )
                        {
                            s = sdsMakeRoomFor (s, l);
                        }
                        memcpy (s + i, buf, l);
                        sdsinclen (s, l);
                        i += l;
                    }
                        break;
                    case 'u':
                    case 'U':
                        if ( next == 'u' )
                            unum = va_arg (ap, unsigned int);
                        else
                            unum = va_arg (ap, unsigned long long);
                    {
                        char buf[SDS_LLSTR_SIZE];
                        l = sdsull2str (buf, unum);
                        if ( sdsavail (s) < l )
                        {
                            s = sdsMakeRoomFor (s, l);
                        }
                        memcpy (s + i, buf, l);
                        sdsinclen (s, l);
                        i += l;
                    }
                        break;
                    default: /* Handle %% and generally %<unknown>. */
                        s[i ++] = next;
                        sdsinclen (s, 1);
                        break;
                }
                break;
            default:
                s[i ++] = * f;
                sdsinclen (s, 1);
                break;
        }
        f ++;
    }
    va_end (ap);

    /* Add null-term */
    s[i] = '\0';
    return s;
}

/* Remove the part of the string from left and from right composed just of
 * contiguous characters found in 'cset', that is a null terminted C string.
 *
 * After the call, the modified sds string is no longer valid and all the
 * references must be substituted with the new pointer returned by the call.
 *
 * Example:
 *
 * s = sdsnew("AA...AA.a.aa.aHelloWorld     :::");
 * s = sdstrim(s,"Aa. :");
 * printf("%s\n", s);
 *
 * Output will be just "Hello World".
 */
sds sdstrim ( sds s, const char *cset )
{
    char *start, *end, *sp, *ep;
    size_t len;

    sp = start = s;
    ep = end = s + sdslen (s) - 1;
    while ( sp <= end && strchr (cset, *sp) ) sp ++;
    while ( ep > sp && strchr (cset, *ep) ) ep --;
    len = ( sp > ep ) ? 0 : ( ( ep - sp ) + 1 );
    if ( s != sp ) memmove (s, sp, len);
    s[len] = '\0';
    sdssetlen (s, len);
    return s;
}

/* Turn the string into a smaller (or equal) string containing only the
 * substring specified by the 'start' and 'end' indexes.
 *
 * start and end can be negative, where -1 means the last character of the
 * string, -2 the penultimate character, and so forth.
 *
 * The interval is inclusive, so the start and end characters will be part
 * of the resulting string.
 *
 * The string is modified in-place.
 *
 * Example:
 *
 * s = sdsnew("Hello World");
 * sdsrange(s,1,-1); => "ello World"
 */
void sdsrange ( sds s, int start, int end )
{
    size_t newlen, len = sdslen (s);

    if ( len == 0 ) return;
    if ( start < 0 )
    {
        start = len + start;
        if ( start < 0 ) start = 0;
    }
    if ( end < 0 )
    {
        end = len + end;
        if ( end < 0 ) end = 0;
    }
    newlen = ( start > end ) ? 0 : ( end - start ) + 1;
    if ( newlen != 0 )
    {
        if ( start >= ( signed )len )
        {
            newlen = 0;
        }
        else if ( end >= ( signed )len )
        {
            end = len - 1;
            newlen = ( start > end ) ? 0 : ( end - start ) + 1;
        }
    }
    else
    {
        start = 0;
    }
    if ( start && newlen ) memmove (s, s + start, newlen);
    s[newlen] = 0;
    sdssetlen (s, newlen);
}

/* Apply tolower() to every character of the sds string 's'. */
void sdstolower ( sds s )
{
    int len = sdslen (s), j;

    for ( j = 0; j < len; j ++ ) s[j] = tolower (s[j]);
}

/* Apply toupper() to every character of the sds string 's'. */
void sdstoupper ( sds s )
{
    int len = sdslen (s), j;

    for ( j = 0; j < len; j ++ ) s[j] = toupper (s[j]);
}

/* Compare two sds strings s1 and s2 with memcmp().
 *
 * Return value:
 *
 *     positive if s1 > s2.
 *     negative if s1 < s2.
 *     0 if s1 and s2 are exactly the same binary string.
 *
 * If two strings share exactly the same prefix, but one of the two has
 * additional characters, the longer string is considered to be greater than
 * the smaller one. */
int sdscmp ( const sds s1, const sds s2 )
{
    size_t l1, l2, minlen;
    int cmp;

    l1 = sdslen (s1);
    l2 = sdslen (s2);
    minlen = ( l1 < l2 ) ? l1 : l2;
    cmp = memcmp (s1, s2, minlen);
    if ( cmp == 0 ) return l1 - l2;
    return cmp;
}

/* Split 's' with separator in 'sep'. An array
 * of sds strings is returned. *count will be set
 * by reference to the number of tokens returned.
 *
 * On out of memory, zero length string, zero length
 * separator, NULL is returned.
 *
 * Note that 'sep' is able to split a string using
 * a multi-character separator. For example
 * sdssplit("foo_-_bar","_-_"); will return two
 * elements "foo" and "bar".
 *
 * This version of the function is binary-safe but
 * requires length arguments. sdssplit() is just the
 * same function but for zero-terminated strings.
 */
sds *sdssplitlen ( const char *s, int len, const char *sep, int seplen, int *count )
{
    int elements = 0, slots = 5, start = 0, j;
    sds *tokens;

    if ( seplen < 1 || len < 0 ) return NULL;

    tokens = s_malloc (sizeof (sds ) * slots);
    if ( tokens == NULL ) return NULL;

    if ( len == 0 )
    {
        *count = 0;
        return tokens;
    }
    for ( j = 0; j < ( len - ( seplen - 1 ) ); j ++ )
    {
        /* make sure there is room for the next element and the final one */
        if ( slots < elements + 2 )
        {
            sds *newtokens;

            slots *= 2;
            newtokens = s_realloc (tokens, sizeof (sds ) * slots);
            if ( newtokens == NULL ) goto cleanup;
            tokens = newtokens;
        }
        /* search the separator */
        if ( ( seplen == 1 && * ( s + j ) == sep[0] ) || ( memcmp (s + j, sep, seplen) == 0 ) )
        {
            tokens[elements] = sdsnewlen (s + start, j - start);
            if ( tokens[elements] == NULL ) goto cleanup;
            elements ++;
            start = j + seplen;
            j = j + seplen - 1; /* skip the separator */
        }
    }
    /* Add the final element. We are sure there is room in the tokens array. */
    tokens[elements] = sdsnewlen (s + start, len - start);
    if ( tokens[elements] == NULL ) goto cleanup;
    elements ++;
    *count = elements;
    return tokens;

cleanup: {
          int i;
          for ( i = 0; i < elements; i ++ ) sdsfree (tokens[i]);
          s_free (tokens);
          *count = 0;
          return NULL;
    }
}

/* Free the result returned by sdssplitlen(), or do nothing if 'tokens' is NULL. */
void sdsfreesplitres ( sds *tokens, int count )
{
    if ( ! tokens ) return;
    while ( count -- )
        sdsfree (tokens[count]);
    s_free (tokens);
}

/* Append to the sds string "s" an escaped string representation where
 * all the non-printable characters (tested with isprint()) are turned into
 * escapes in the form "\n\r\a...." or "\x<hex-number>".
 *
 * After the call, the modified sds string is no longer valid and all the
 * references must be substituted with the new pointer returned by the call. */
sds sdscatrepr ( sds s, const char *p, size_t len )
{
    s = sdscatlen (s, "\"", 1);
    while ( len -- )
    {
        switch ( *p )
        {
            case '\\':
            case '"':
                s = sdscatprintf (s, "\\%c", *p);
                break;
            case '\n': s = sdscatlen (s, "\\n", 2);
                break;
            case '\r': s = sdscatlen (s, "\\r", 2);
                break;
            case '\t': s = sdscatlen (s, "\\t", 2);
                break;
            case '\a': s = sdscatlen (s, "\\a", 2);
                break;
            case '\b': s = sdscatlen (s, "\\b", 2);
                break;
            default:
                if ( isprint (*p) )
                    s = sdscatprintf (s, "%c", *p);
                else
                    s = sdscatprintf (s, "\\x%02x", ( unsigned char ) *p);
                break;
        }
        p ++;
    }
    return sdscatlen (s, "\"", 1);
}

/* Helper function for sdssplitargs() that returns non zero if 'c'
 * is a valid hex digit. */
int is_hex_digit ( char c )
{
    return (c >= '0' && c <= '9' ) || ( c >= 'a' && c <= 'f' ) ||
        ( c >= 'A' && c <= 'F' );
}

/* Helper function for sdssplitargs() that converts a hex digit into an
 * integer from 0 to 15 */
int hex_digit_to_int ( char c )
{
    switch ( c )
    {
        case '0': return 0;
        case '1': return 1;
        case '2': return 2;
        case '3': return 3;
        case '4': return 4;
        case '5': return 5;
        case '6': return 6;
        case '7': return 7;
        case '8': return 8;
        case '9': return 9;
        case 'a': case 'A': return 10;
        case 'b': case 'B': return 11;
        case 'c': case 'C': return 12;
        case 'd': case 'D': return 13;
        case 'e': case 'E': return 14;
        case 'f': case 'F': return 15;
        default: return 0;
    }
}

/* Split a line into arguments, where every argument can be in the
 * following programming-language REPL-alike form:
 *
 * foo bar "newline are supported\n" and "\xff\x00otherstuff"
 *
 * The number of arguments is stored into *argc, and an array
 * of sds is returned.
 *
 * The caller should free the resulting array of sds strings with
 * sdsfreesplitres().
 *
 * Note that sdscatrepr() is able to convert back a string into
 * a quoted string in the same format sdssplitargs() is able to parse.
 *
 * The function returns the allocated tokens on success, even when the
 * input string is empty, or NULL if the input contains unbalanced
 * quotes or closed quotes followed by non space characters
 * as in: "foo"bar or "foo'
 */
sds *sdssplitargs ( const char *line, int *argc )
{
    const char *p = line;
    char *current = NULL;
    char **vector = NULL;

    *argc = 0;
    while ( 1 )
    {
        /* skip blanks */
        while ( *p && isspace (*p) ) p ++;
        if ( *p )
        {
            /* get a token */
            int inq = 0; /* set to 1 if we are in "quotes" */
            int insq = 0; /* set to 1 if we are in 'single quotes' */
            int done = 0;

            if ( current == NULL ) current = sdsempty ();
            while ( ! done )
            {
                if ( inq )
                {
                    if ( *p == '\\' && * ( p + 1 ) == 'x' &&
                         is_hex_digit (*( p + 2 )) &&
                         is_hex_digit (*( p + 3 )) )
                    {
                        unsigned char byte;

                        byte = ( hex_digit_to_int (*( p + 2 ))*16 ) +
                            hex_digit_to_int (*( p + 3 ));
                        current = sdscatlen (current, ( char* ) &byte, 1);
                        p += 3;
                    }
                    else if ( *p == '\\' && * ( p + 1 ) )
                    {
                        char c;

                        p ++;
                        switch ( *p )
                        {
                            case 'n': c = '\n';
                                break;
                            case 'r': c = '\r';
                                break;
                            case 't': c = '\t';
                                break;
                            case 'b': c = '\b';
                                break;
                            case 'a': c = '\a';
                                break;
                            default: c = * p;
                                break;
                        }
                        current = sdscatlen (current, &c, 1);
                    }
                    else if ( *p == '"' )
                    {
                        /* closing quote must be followed by a space or
                         * nothing at all. */
                        if ( *( p + 1 ) && ! isspace (*( p + 1 )) ) goto err;
                        done = 1;
                    }
                    else if ( ! *p )
                    {
                        /* unterminated quotes */
                        goto err;
                    }
                    else
                    {
                        current = sdscatlen (current, p, 1);
                    }
                }
                else if ( insq )
                {
                    if ( *p == '\\' && * ( p + 1 ) == '\'' )
                    {
                        p ++;
                        current = sdscatlen (current, "'", 1);
                    }
                    else if ( *p == '\'' )
                    {
                        /* closing quote must be followed by a space or
                         * nothing at all. */
                        if ( *( p + 1 ) && ! isspace (*( p + 1 )) ) goto err;
                        done = 1;
                    }
                    else if ( ! *p )
                    {
                        /* unterminated quotes */
                        goto err;
                    }
                    else
                    {
                        current = sdscatlen (current, p, 1);
                    }
                }
                else
                {
                    switch ( *p )
                    {
                        case ' ':
                        case '\n':
                        case '\r':
                        case '\t':
                        case '\0':
                            done = 1;
                            break;
                        case '"':
                            inq = 1;
                            break;
                        case '\'':
                            insq = 1;
                            break;
                        default:
                            current = sdscatlen (current, p, 1);
                            break;
                    }
                }
                if ( *p ) p ++;
            }
            /* add the token to the vector */
            vector = s_realloc (vector, ( ( *argc ) + 1 ) * sizeof (char* ));
            vector[*argc] = current;
            ( *argc ) ++;
            current = NULL;
        }
        else
        {
            /* Even on empty input string return something not NULL. */
            if ( vector == NULL ) vector = s_malloc (sizeof (void* ));
            return vector;
        }
    }

err:
    while ( ( *argc ) -- )
        sdsfree (vector[*argc]);
    s_free (vector);
    if ( current ) sdsfree (current);
    *argc = 0;
    return NULL;
}

/* Modify the string substituting all the occurrences of the set of
 * characters specified in the 'from' string to the corresponding character
 * in the 'to' array.
 *
 * For instance: sdsmapchars(mystring, "ho", "01", 2)
 * will have the effect of turning the string "hello" into "0ell1".
 *
 * The function returns the sds string pointer, that is always the same
 * as the input pointer since no resize is needed. */
sds sdsmapchars ( sds s, const char *from, const char *to, size_t setlen )
{
    size_t j, i, l = sdslen (s);

    for ( j = 0; j < l; j ++ )
    {
        for ( i = 0; i < setlen; i ++ )
        {
            if ( s[j] == from[i] )
            {
                s[j] = to[i];
                break;
            }
        }
    }
    return s;
}

/* Join an array of C strings using the specified separator (also a C string).
 * Returns the result as an sds string. */
sds sdsjoin ( char **argv, int argc, char *sep )
{
    sds join = sdsempty ();
    int j;

    for ( j = 0; j < argc; j ++ )
    {
        join = sdscat (join, argv[j]);
        if ( j != argc - 1 ) join = sdscat (join, sep);
    }
    return join;
}

/* Like sdsjoin, but joins an array of SDS strings. */
sds sdsjoinsds ( sds *argv, int argc, const char *sep, size_t seplen )
{
    sds join = sdsempty ();
    int j;

    for ( j = 0; j < argc; j ++ )
    {
        join = sdscatsds (join, argv[j]);
        if ( j != argc - 1 ) join = sdscatlen (join, sep, seplen);
    }
    return join;
}

/* Wrappers to the allocators used by SDS. Note that SDS will actually
 * just use the macros defined into sdsalloc.h in order to avoid to pay
 * the overhead of function calls. Here we define these wrappers only for
 * the programs SDS is linked to, if they want to touch the SDS internals
 * even if they use a different allocator. */
void *sds_malloc ( size_t size )
{
    return s_malloc (size);
}

void *sds_realloc ( void *ptr, size_t size )
{
    return s_realloc (ptr, size);
}

void sds_free ( void *ptr )
{
    s_free (ptr);
}

#if defined(SDS_TEST_MAIN)
#include <stdio.h>
#include "../lib/testhelp.h"
#include "../lib/limits.h"

#define UNUSED(x) (void)(x)

int sdsTest ( void )
{
    {
        sds x = sdsnew ("foo"), y;

        test_cond ("Create a string and obtain the length",
                   sdslen (x) == 3 && memcmp (x, "foo\0", 4) == 0)

            sdsfree (x);
        x = sdsnewlen ("foo", 2);
        test_cond ("Create a string with specified length",
                   sdslen (x) == 2 && memcmp (x, "fo\0", 3) == 0)

            x = sdscat (x, "bar");
        test_cond ("Strings concatenation",
                   sdslen (x) == 5 && memcmp (x, "fobar\0", 6) == 0);

        x = sdscpy (x, "a");
        test_cond ("sdscpy() against an originally longer string",
                   sdslen (x) == 1 && memcmp (x, "a\0", 2) == 0)

            x = sdscpy (x, "xyzxxxxxxxxxxyyyyyyyyyykkkkkkkkkk");
        test_cond ("sdscpy() against an originally shorter string",
                   sdslen (x) == 33 &&
                   memcmp (x, "xyzxxxxxxxxxxyyyyyyyyyykkkkkkkkkk\0", 33) == 0)

            sdsfree (x);
        x = sdscatprintf (sdsempty (), "%d", 123);
        test_cond ("sdscatprintf() seems working in the base case",
                   sdslen (x) == 3 && memcmp (x, "123\0", 4) == 0)

            sdsfree (x);
        x = sdsnew ("--");
        x = sdscatfmt (x, "Hello %s World %I,%I--", "Hi!", LLONG_MIN, LLONG_MAX);
        test_cond ("sdscatfmt() seems working in the base case",
                   sdslen (x) == 60 &&
                   memcmp (x, "--Hello Hi! World -9223372036854775808,"
                           "9223372036854775807--", 60) == 0)
            printf ("[%s]\n", x);

        sdsfree (x);
        x = sdsnew ("--");
        x = sdscatfmt (x, "%u,%U--", UINT_MAX, ULLONG_MAX);
        test_cond ("sdscatfmt() seems working with unsigned numbers",
                   sdslen (x) == 35 &&
                   memcmp (x, "--4294967295,18446744073709551615--", 35) == 0)

            sdsfree (x);
        x = sdsnew (" x ");
        sdstrim (x, " x");
        test_cond ("sdstrim() works when all chars match",
                   sdslen (x) == 0)

            sdsfree (x);
        x = sdsnew (" x ");
        sdstrim (x, " ");
        test_cond ("sdstrim() works when a single char remains",
                   sdslen (x) == 1 && x[0] == 'x')

            sdsfree (x);
        x = sdsnew ("xxciaoyyy");
        sdstrim (x, "xy");
        test_cond ("sdstrim() correctly trims characters",
                   sdslen (x) == 4 && memcmp (x, "ciao\0", 5) == 0)

            y = sdsdup (x);
        sdsrange (y, 1, 1);
        test_cond ("sdsrange(...,1,1)",
                   sdslen (y) == 1 && memcmp (y, "i\0", 2) == 0)

            sdsfree (y);
        y = sdsdup (x);
        sdsrange (y, 1, - 1);
        test_cond ("sdsrange(...,1,-1)",
                   sdslen (y) == 3 && memcmp (y, "iao\0", 4) == 0)

            sdsfree (y);
        y = sdsdup (x);
        sdsrange (y, - 2, - 1);
        test_cond ("sdsrange(...,-2,-1)",
                   sdslen (y) == 2 && memcmp (y, "ao\0", 3) == 0)

            sdsfree (y);
        y = sdsdup (x);
        sdsrange (y, 2, 1);
        test_cond ("sdsrange(...,2,1)",
                   sdslen (y) == 0 && memcmp (y, "\0", 1) == 0)

            sdsfree (y);
        y = sdsdup (x);
        sdsrange (y, 1, 100);
        test_cond ("sdsrange(...,1,100)",
                   sdslen (y) == 3 && memcmp (y, "iao\0", 4) == 0)

            sdsfree (y);
        y = sdsdup (x);
        sdsrange (y, 100, 100);
        test_cond ("sdsrange(...,100,100)",
                   sdslen (y) == 0 && memcmp (y, "\0", 1) == 0)

            sdsfree (y);
        sdsfree (x);
        x = sdsnew ("foo");
        y = sdsnew ("foa");
        test_cond ("sdscmp(foo,foa)", sdscmp (x, y) > 0)

        sdsfree (y);
        sdsfree (x);
        x = sdsnew ("bar");
        y = sdsnew ("bar");
        test_cond ("sdscmp(bar,bar)", sdscmp (x, y) == 0)

        sdsfree (y);
        sdsfree (x);
        x = sdsnew ("aar");
        y = sdsnew ("bar");
        test_cond ("sdscmp(bar,bar)", sdscmp (x, y) < 0)

        sdsfree (y);
        sdsfree (x);
        x = sdsnewlen ("\a\n\0foo\r", 7);
        y = sdscatrepr (sdsempty (), x, sdslen (x));

        test_cond ("sdscatrepr(...data...)",
                   memcmp (y, "\"\\a\\n\\x00foo\\r\"", 15) == 0)

        {
            unsigned int oldfree;
            char *p;
            int step = 10, j, i;

            sdsfree (x);
            sdsfree (y);
            x = sdsnew ("0");
            test_cond ("sdsnew() free/len buffers", sdslen (x) == 1 && sdsavail (x) == 0);

            /* Run the test a few times in order to hit the first two
             * SDS header types. */
            for ( i = 0; i < 10; i ++ )
            {
                int oldlen = sdslen (x);
                x = sdsMakeRoomFor (x, step);
                int type = x[- 1] & SDS_TYPE_MASK;

                test_cond ("sdsMakeRoomFor() len", sdslen (x) == oldlen);
                if ( type != SDS_TYPE_5 )
                {
                    test_cond ("sdsMakeRoomFor() free", sdsavail (x) >= step);
                    oldfree = sdsavail (x);
                }
                p = x + oldlen;
                for ( j = 0; j < step; j ++ )
                {
                    p[j] = 'A' + j;
                }
                sdsIncrLen (x, step);
            }
            test_cond ("sdsMakeRoomFor() content",
                       memcmp ("0ABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJ", x, 101) == 0);
            test_cond ("sdsMakeRoomFor() final length", sdslen (x) == 101);

            sdsfree (x);
        }
    }
    test_report ()
    return 0;
}
#endif

#ifdef SDS_TEST_MAIN

int main ( void )
{
    return sdsTest ();
}
#endif
